Smile And Say "Fat!"

For weeks, Hollywood stars have lip-plumped and lasered themselves in preparation for the red carpet photographers at the Academy Awards. Celebrities have many reasons to fear the camera: Just look at Tyra Banks, who recently blamed bad camera angles after tabloids caught the former model sporting flab in a bathing suit and dubbed her "Thigh-ra Banks." So why do cameras add 10 pounds?

Bad lighting, mostly. The flat, even illumination on the red carpet makes it hard for the camera to capture dimension, unlike in a photo shoot with flattering soft lights. Cast from an angle, light creates shadows that sculpt the face and body by hiding unwanted flesh. Softer lights can hide wrinkles and smooth out the skin for women, while harsher lights on male faces exaggerate lines for a chiseled look. Without the aid of shadows, however, light exposes the imperfections of the face and body and makes the resulting image bigger and flatter. That's why everyone avoids white dresses—which cast fewer shadows under even lighting—except the thinnest actresses, like Nicole Kidman.

The camera's perspective—how objects in a two-dimensional field express depth—can also distort a person's size. Telephoto lenses, which have a long focal length, compress the space between the foreground and the background, making distant objects appear closer. Up close, they shrink the distance from your nose to your ears, resulting in a diminished proboscis and more balanced features. (That's why paparazzi use telephoto lenses—for flattery as well as magnification.) Wide angle lenses, which have a short focal length, do just the opposite, making a person in the center of the picture appear both wider and taller. At the extreme, these lenses can also make people at the outside edges of a group photo look fatter.

But a celebrity can look fat on camera even with ideal lighting and focal length. Distortions will be introduced any time you try to project a three-dimensional object onto the two-dimensional surface of a photograph. (Just compare globes with maps, which always make things look a little funny.) That's one excuse for retouching celebrity photos. A few clicks of the mouse can draw in the waistline and add a few inches in height.

Bonus Explainer: Why is it sometimes hard to recognize ourselves in videos and photos? Because the image isn't flipped. We're most used to seeing our own bodies in the mirror, where our features are reversed left to right. It's similar to how our voices sound unfamiliar and higher on a tape recording. We're expecting to hear ourselves as we usually do, with the sounds we make traveling through the bones in our face to reach our ears.

Got a question about today's news? Ask the Explainer.

The Explainer thanks Don Ayotte of Hallmark Institute of Photography, Marty Banks of UC Berkeley, Bob Gann of Hewlett-Packard, Doug Manchee of Rochester Institute of Technology, and Mary Peterson of the University of Arizona